Conversions of Alcohols to Alkyl Halides

The Diels-Alder reaction was discovered and named after the Nobel Prize winning scientists Kurt Alder and Otto Diels in 1928. Such a reaction occurs when a diene with two adjacent double bonds is mixed with a dienophile consisting of a double bond in order to create a cyclohexene. The diene must be in the s-cis conformation in order for the electron transfer to engage correctly. If the diene in question is in s-trans conformation then the access to the molecules is limited, thus, no reaction can occur. The dienophile we used was maleic anhydride. Maleic anhydride possesses high electron withdrawing characteristics which caused a very quick reaction. The reaction will

(Q4:SN2 Rxn) SN2 reactions occur when a primary alkyl halide (benzyl bromide – electrophile) is made to react with a nucleophile (the unknown reactant) in a strong base solution (sodium hydroxide). The hydroxide anion from the strong base can also act as a strong nucleophile which allows for the deprotonation of the unknown thereby leaving the unknown’s oxygen with a negative charge. The deprotonation of the unknown allows for the formation of a water molecule. The bromide in the benzyl bromide is a great leaving group

A unimolecular nucleophilic substitution or SN1 is a two-step reaction that occurs with a first order reaction. The rate-limiting step, which is the first step, forms a carbocation. This would be the slowest step in the mechanism. The addition of the nucleophile speeds up the reaction and stabilizes the carbocation. This reaction is more favorable with tertiary and sometimes secondary alkyl halides under strong basic or acidic conditions with secondary or tertiary alcohols. In this experiment, the t-butyl halide underwent an SN1 reaction. Nucleophiles do not necessarily effect the reaction because the nucleophile is considered zero order, (which makes it a first order reaction.) The ion that should have the strongest effect in an SN1 reaction is the bromide ion. The bromide ion should be stronger because it has a lower electronegativity than chloride as well as a smaller radius.

The purpose of this experiment is to examine the reactivities of various alkyl halides under both SN2 and SN1 reaction conditions. The alkyl halides will be examined based on the substrate types and solvent the reaction takes place in.

The mechanism of an SN1 reaction is consistent. First, the leaving group leaves forming the carbocation. The intermediate carbocation is planar and achiral. The nucleophile is then free to attack from either side of the carbocation, which forms the substituted product in either a racemic mixture or with some form of

Discussion: An E1 reaction mechanism is a unimolecular elimination reaction in which a carbocation is formed as an intermediate in the multistep reaction. E1 reactions typically occur under conditions with a non-basic nucleophile and with protic solvents, meaning a solvent containing an –OH or –NH bond. These reactions also represent first-order kinetics, meaning that the concentration of the nucleophile will not appear in the rate equation. In this reaction, 4-methylcyclohexanol is acting as a nucleophile and grabs a proton from the sulfuric acid.

When an enzyme pairs with a substrate there are one of two ways this may occur. The lock and key model refers to a reaction in which the substrate will perfectly fit the active site of an enzyme, while the induced fit model involves a conformational change of both the enzyme and the substrate (Ophardt, 2003). The overall reaction is summarized by the following: initiation is characterized by substrate binding the enzyme at its active site and forming the enzyme-substrate complex at a rate of k1 over k-1 (forward and reverse rates respectively), this is followed by formation/dissociation of the enzyme with product at a rate of k2 (Figure 1) (ChemWiki, 2013). This reaction highlights the basis of enzyme kinetics in that an enzyme and a substrate can progress to a dissociated enzyme and a product, or move in reverse and never form a product. There are also more complicated instances in which there exists an enzyme-product complex or an enzyme-intermediate complex, though these will not be discussed further

Using various alcohols, the substitution reactions (Sn2 and Sn) were utilized by helping with which functional groups reacted, in which way. Developing a mechanism for the alcohols are discussed.

Next, the stages of the reaction form a cyclic pathway known as the Krebs Cycle. Each turn creates one ATP. Since it's happening twice, then there are two as a result of Krebs.

vibrate. These vibrations are what cause the two to collide; and when the enzyme and

Lys-691 creates a hydrogen bond to the substrate but also stabilizes the negatively charged oxygen of the mevaldyl-CoA the linkages of hydrogen bonds and ionic bonds. Probably, this also affects the formation of the intermediate products and transitions states that lead to their formation. It is known that these processes also lower the activation energy for the first step of reactions so that they can occur very easily (Figure 5).

Then, a shift is observed by one of the atoms to the carbocation. And finally, to stabilize the molecule, catalyst is then regenerated to yield the final product.

The first of the two common pathways is the 5’ to 3’ pathway. First, decapping enzymes comprising of

credit annotated diagrams QWC – clear, well organised using specialist terms ; award QWC mark if three of the following are used photophosphorylation cristae glycolysis photolysis Calvin cycle link reaction Krebs cycle dehydrogenase / dehydrogenation

Alcohol dependence (alcoholism), occurs when the body cannot function without the effect of alcohol. Alcohol affects specific neurotransmitters in the brain and when the brain becomes accustomed to the alcohols affects it can no longer function properly signals without the help of the alcohol. Once someone has developed a dependency on alcohol, they will continue to drink regardless of any serious physical complications that are caused by alcohol.